Tube closure



A ril 28, 1964 E. RAAMAT 3,130,898

TUBE CLOSURE Filed Jan. 11, 1962 INVENTOR ERIC RAAMAT PATENT AGENTUnited States Patent 3,130,898 TUBE CLOSURE Eric Raamat, Toronto,Ontario, Canada, assignor to Tube- Vent Limited, Toronto, Ontario,Canada Filed Jan. 11, 1962, Ser. No. 165,688 1 Claim. (Cl. 229--93) Thisinvention relates to tube closures for deformable tubes and to themethod of achieving such closures.

It is an object of this invention to provide a tube closure suitable fora deformable tube which may be simply and conveniently provided, toclose the end of a tube and which may be easily opened or reclosed.

It is an object of this invention to provide a deformable tube designedand constructed so that the novel closure may easily be attained.

It is an object of this invention to provide a method of closing tubesin a simple and novel manner.

The closure, in accord with the invention is adapted to be applied totubes having at at least one end an exposed or free edge and the closureis applied between two points on said edge where the straight linebetween the two points is shorter than the edge extent therebetween.With this arrangement it will be seen that the edge extent will, viewedalong the axis of the tube, be concave inward relative to the linejoining said two points. In accord with the invention, a closure isprovided for such tube by deforming the material at and adjacent saidedge extent inwardly relative to said tube axis about a crease lineextending between said two points and therebetween through the tubematerial. The material deformed inwardly relative to such line tends toform, relative to the crease line, a curve which is reversed from theunde formed curve. Relative to the plane including said two points andthe portion of said crease line farthest from said edge, the curve ofthe edge after deformation is the mirror image of that beforedeformation. Since the distance through the material, between two pointson the crease line which are on the same plane perpendicular to the tubeaxis, is longer than the straight line distance therebetween, there isan over-centre effect which tends to hold the material in its newposition providing a tube closure which is secure, but is easily removedto remove material from the tube.

In a preferred embodiment of the invention two such closures areprovided at each end of the tube. Each closure is approximatelydiametrically opposed to the other across the tube, and is made of suchdepth that the two closures in effect close the tube.

In drawings which illustrate a preferred embodiment of the invention;

FIGURE 1 illustrates a tube to which such closure may be applied.

FIGURE 2 shows a means suitable for applying such closure; and

FIGURE 3 shows a tube with the closure applied.

In the drawings, there is shown, a tube of cardboard or other semi-rigiddeformable material not subject to any substantial stretching under thenormal bending and creasing operations. The invention is described inrela tion to a cylindrical tube although it will be appreciated thattubes of other form of cross-section could be used as long as the tubeis, where the closure is applied, concave inward toward the axis.

3,130,898 Patented Apr. 28, 1964 In FIGURE 3 are shown points 12 and 14,located on' strai ht line distance therebetween. It will be seentherefore, that the edge 16 may be deformed inwardly and downwardly todefine the crease line 18 which joins the points 12 and 14 through thecarton material. It will be seen that the edge 16 and each line throughthe deformed material will be curved, as a mirror image of the curvaturebefore deformation, and that in view of this inverse curvature thematerial itself resists movement back to the original undeformed shapeand there is thus an overcenter effect tending to retain the closure.

With a cylindrical tube the best closure is achieved with two closuresof the type described above diametrically opposing each other and withthe opposing but approaching edges 16 as close as possible one to theother. The best closure is also attained, with a tube of circularcross-section when the tube is deformed between the two sets of points12 and 14, to provide a contour which, when viewed along an axisperpendicular to that of the tube and perpendicular to a line joiningthe points 12 and 14, is an arc of the circle. It will be appreciatedthat this closure can be performed manually with the thumb or finger.However in FIGURE 2 is shown a method whereby manufactured tubes may beprovided with crease lines 18 in advance to allow for easy closure ofthe ends of the tubes, in accord with the invention, at a later time. InFIGURE 2 clamping means 20, as illustrated, holds a tube in positionwhile a pair of cylindrical members 22, of a diameter approximately lessthan the diameter of the inside of the tube, by twice the thickness ofthe tube mate rial, is used for deformation. The lower halves of thecylindrical cross-section of members 22 are brought into contact withthe tube as indicated in FIGURE 2 and although in FIGURE 2; forillustration, one of the deforming members 22 is shown approaching thetube and the other deforming member 22 is shown in contact with thetube, it would be appreciated, that in practice, the better method willbe to have the two deforming members approach the tube simultaneouslyfrom opposite sides and contact it at the same time. When this has beendone it will be seen that the deformable tube is provided with a creaseline 18 simplifying the operation of providing a closure for a personusing the tube. In most tubes the deformation illustrated in FIGURE 2will be performed at both ends and after the deformation in each case,the closure portion, being the smaller portion defined by the creaseline 18, is snapped back to normal position in line with the remainderof the contour of the tube so that the tube again assumes the formindicated in FIGURE 1. The tube may then be sold, or provided witharticles suitable for mailing in such tube, and the user of the tube maypick up the tube with the crease line but otherwise in the contour ofFIGURE 1, insert the article in the tube and with his thumb or fingerachieve the closure at both ends of the tube which is then ready formailing.

In this way a convenient and secure closure is obtained which may beeasily opened when required.

I claim:

A tube of cardboard defining a hollow cross-section having length andwidth; the material forming said tube terminating at at least one endthereof in a free edge; a pair of opposed portions of said free edgebeing deformed 3 4 inwardly at a 90 angle relative to said tube; eachporeach provide a surface extending substantially perpendicution beingdeformed between two points on said edge to lar to the axis of the tube.form a crease line terminating at each end of said edge; each area ofdeformed material forming about the plane References Cited ill the fileof this Patent defined by said two points and the intermediate creaseline, 5 UNITED STATES PATENTS a mirror image of its form beforedeformation; and wherein said deformed areas close a major portion ofthe end g gg g ii of the tube whereby said respective deformed edges are2,194,904 Jackson Mar. 1940 immediately adjacent one another and saiddeformed areas

